The market for thermal imaging systems is large and growing quickly, and is driven by military, security, medical, construction, and automotive markets. Thermal imaging systems typically image thermal wavelengths that scenes at “normal” environmental temperatures, e.g., room or body temperature, radiate. Useful wavelengths for imaging applications include those that the atmosphere readily transmits, and that are not overwhelmed by radiation of the same wavelength from the sun. Thus, thermal imaging systems typically image long wavelength infrared radiation (LWIR), e.g., wavelengths in the range of 7 to 15 microns, that a scene radiates.
Systems that image long wavelength infrared radiation from scenes include narrow-bandgap semiconductor photodetector arrays, which typically require cryogenic cooling, and uncooled microbolometer arrays. These kinds of systems are typically so expensive as to make them inaccessible for the majority of commercial and consumer markets. Additionally, the low yield in producing the array elements for these kinds of systems, and the resulting high cost of manufacturing them, makes it impractical to build high-resolution systems for any but the most cost-insensitive uses.